Leakage diagnostics, sealant longevity, sizing and technology transfer in residential thermal distribution systems

Walker, Iain S.; Sherman, Max H.; Modera, Mark; Siegel, Jeffrey A.

doi:10.2172/650258

Cited by 27 publications

(49 citation statements)

References 4 publications

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“…In the study, we used a digital pressure gauge connected with a tube going through a sealed register-size pan, which was designed to fully block a register to obtain static pressure across the block during normal system operation. Its key advantage over the direct register pressure measurement is that it is much more repeatable, as was also indicated by Walker et al 1998.…”

Section: Effective Leakage Areamentioning

confidence: 97%

“…The estimated air leakage ratio for the return section is 6% if based on the pressure-pan measurements, and is 23% based on the method of half plenum pressure. As discussed in the approach section, Walker et al (1998) have used essentially the same method to estimate air leakage from residential ducts, and they estimated that the maximum uncertainty was 40% of the measured air-leakage rate.…”

Section: Air Leakage Ratiomentioning

confidence: 99%

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Performance of thermal distribution systems in large commercial buildings

Xu¹,

Carrié²,

Dickerhoff³

et al. 2002

Energy and Buildings

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This paper presents major findings of a field study on the performance of five thermal distribution systems in four large commercial buildings. The five systems studied are typical single-duct or dual-duct constant air volume (CAV) systems and variable air volume (VAV) systems, each of which serves an office building or a retail building with floor area over 2,000 m 2 . The air leakage from ducts are reported in terms of effective leakage area (ELA) at 25 Pa reference pressure, the ASHRAE-defined duct leakage class, and air leakage ratios.The specific ELAs ranged from 0.7 to 12.9 cm 2 per m 2 of duct surface area, and from 0.1 to 7.7 cm 2 per square meter of floor area served. The leakage classes ranged from 34 to 757 for the five systems and systems sections tested. The air leakage ratios are estimated to be up to one-third of the fan-supplied airflow in the constant-air-volume systems. The specific ELAs and leakage classes indicate that air leakage in large commercial duct systems varies significantly from system to system, and from system section to system section even within the same thermal distribution system. The duct systems measured are much leakier than the ductwork specified as "unsealed ducts" by ASHRAE. Energy losses from supply ducts by conduction (including convection and radiation) are found to be significant, on the scale Page lof29LBNL-44331 similar to the losses induced by air leakage in the duct systems. The energy losses induced by leakage and conduction suggest that there are significant energy-savings potentials from duct-sealing and insulation practice in large commercial buildings.

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Section: Effective Leakage Areamentioning

confidence: 97%

Section: Air Leakage Ratiomentioning

confidence: 99%

Performance of thermal distribution systems in large commercial buildings

Xu¹,

Carrié²,

Dickerhoff³

et al. 2002

Energy and Buildings

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show abstract

“…The characteristic pressures, ∆P s and ∆P r , sometimes can be measured, typically at the air-handler plenums or some fraction thereof, but in most situations the pressure at the leak site is unknown and it is advantageous to let these pressures be determined by best fits to the ∆Q and ∆P measurements. Analysis of many DeltaQ tests has shown that fitting to the measured data is more robust if the duct leakage pressure exponents are fixed 9,10 . In particular, experiments to characterize the pressure exponents for a wide range of duct configurations have shown that a value of 0.6 is suitable for most duct systems.…”

Section: Figure 2 Example Of Deltaq Airflow and Pressure Test Datamentioning

confidence: 99%

Heating, Ventilating, and Air-Conditioning: Recent Advances in Diagnostics and Controls to Improve Air-Handling System Performance

Wray¹,

Sherman²,

Walker³

et al. 2008

AIP Conference Proceedings

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Abstract. The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems.

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“…The method consists of blocking the registers one by one with other registers open as normal and recording the pressure difference across the block. Its key advantage over the direct register pressure measurement using a single tube-probe connected to pressure transducers is that it is much more repeatable (Walker et al 1998). …”

Section: Duct System Pressure Measurementsmentioning

confidence: 99%

“…Measuring air leakage flow rates remains a challenging task despite the considerable efforts undertaken in this area (Walker et al 1998;Fisk et al 1998). In this study we use two methods for measuring these air leakage flow rates through duct systems: 1) air leakage flow rates estimated from ELAs and operating pressures, and 2) air leakage flow rates estimated from upstream duct flow and register flows.…”

Section: Duct Air Leakage Flow Ratesmentioning

confidence: 99%